#include <stdio.h>
#include<assert.h>
char* my_strcat(char* dest, char* src)
{
	assert(dest && src);
	char* ret = dest;
	while (*dest != '\0')
	{
		dest++;
	}
	while (*dest++ = *src++);
	return ret;
}
int main()
{
	char str1[] = " world ";
	char str2[20] = "hello";
	printf("%s\n", my_strcat(str2, str1));
	return 0;
}